Releasing or nonreleasing clamp



June 19, 1934. JESTER 1,963,848

RELEASING OR NONRELEASING CLAMP Filed Aug. 11, 1930 2 Sheets-Sheet l June 19, 1934. JESTER 1,963,848

RELEASING OR NONRELEASING CLAMP Filed Aug. 11, 1930 2 Sheets-Sheet 2 Patented June 19, 1934 UNITED STATES PATENT OFFICE 12 Claims.

The invention relates to clamps employed 'for suspending conductors such as are used in high tension transmission lines.

It-is well known that it is customary to suspend conductors by means of clamps carried by strings of insulators hung from towers which are frequently located long distances apart. It frequently occurs that sleet or ice may accumulat-e upon the conductor at one side of a tower 1- and not at the other side owing to the existence of-local storms and the difference in atmospheric conditions along the line. Furthermore, particularly where the line passesover the mountains or valleys, high winds may cause the bringing of a greater pressure upon the conductor at one side of a tower. Regardless of which may be the case, the fact remains that the strain is unequally distributed as that portion of the conductor which is coated with ice or sleet or that 1 L portion which is subjected to the action of high winds exerts a greater strain at one side of the -a clamp of this character which may be so tower than at the other. This is highly objection- 'ab'le and it has occurred that towers have been pulled over. It is, of course, desirable to build the towers as light as possible to withstand the service for which they are intended and it is not practical to make them so strong as to be capable ofwithstanding every conceivable strain.

With the above facts in View I have devised the present invention which has for its general object the provision of a suspension clamp adapted to open and release the conductor upon the occurrence of an excessive strain at one side m the other of "a tower so that the conductor may slide through until the strain is equalized, thus relieving the tower of those forces tending to pull it over. p

An importantobject of the invention is to 0 provide a clamp for this purpose which is capable 1 position with respect to the normal or vertical,

of maintaining its grip until the string of insulators from which it is suspended has been pulled through an arc of a certain predetermined extent or moved into a certain angular release occurring only after the safe angle of inclination has been passed.

An important object of the invention is to proan a clamp which embodies bolt means for r a11 maintaining a positive grip upon the "'dlimit.

"-conductortogether with trip operated means for rendering the bolt means ineffective upon the occurrence of a force tending to swing the clamp "audits suspending insulators beyond a certain Another object is to provide a clamp having suspension means located at the longitudinal axis of the conductor so that the clamp may accommodate itself to vibrations of the conductor,

or dancing of the cables without bringing any bending strains upon the conductor such as, might in time weaken the fibers thereof and decrease its tensile strength.

Another and. an important object of the invention is to provide a clamp which by the omis- 5 s'ion of a single element may be converted from the releasing into the non-releasing type, it being readily understood that in certain localities where,

there is no freezing weather for instance there may be no necessity for a clamp capable of .re-

, leasing, the adaptability therefore making it possible to reduce the number of clamps necessary to be carried in stock by the manufacturer or installer to take care of various different conditions met with in different sections-of the country. 25

Anotherobject of the invention is to provide ,force tending to swing the clamp and its supporting insulators beyond the predetermined limit, these alternative operations being dependent upon simply the shape of the elements cooperating with the :bolt means for rendering the 8. same ineffective under certain cond tions.

; An additional object is to provide a clamp of character which will be simple and inexpensive to manufacture, as easy to assemble as H one of the ordinary type, positive in action, ef- .ficient and durable in service, and a general improvement in the art.

To the attainment of the foregoing and other objects and advantages, the invention preferably consists in the details of construction and the $5 arrangement and combination of parts to ,be hereinafter more fully described and claimed, and illustrated in the accompanying drawings in which:

Figure l is a side elevation of the clamp, with "one of the bolt means in section and showing the normal position by full lines and the released position -by dotted lines,

Figure v2 is a horizontal section taken on the line 2"2 of Figure 1,

Figure 3 is a vertical cross section taken on the line 3-301 Figure :2,

Figure 4 is a plan view of the upper clamping member alone,

Figure 5 is an and elevation thereof,

j conductor at any time and Figure 6 is a detail plan view of the shiftable bolt engaging member or trigger,

Figure '7 is a side elevation of the clamp showing a modification capable of regripping the cable after return of the parts to normal position,

Figure 8 is a similar view showing spring reactance associated with the securing bolts,

Figure 9 is a side elevation showing the clamp converted into one of the non-releasing type.

Referring more particularly to the drawings I have shown my clamp as comprising a lower member 10 preferably formed as a casting and provided with a longitudinally extending seat or groove 11 for the reception of the conductor 12, this seat being curved in cross section preferably to conform substantially to the curvature of the conductor though there may be some variation in this respect. Furthermore it is preferable that the ends of this member be outwardly flared or more or less of bell shape as indicated at 13, the ends of the seat being cor-. respondingly outwardly curved so as to avoid contact of the ends of this member with the thereby eliminate the bringing of any bending strains upon the conductor during vibration or dancing thereof as occurs for example in windy weather. The e xact mechanical construction of this member is more or less immaterial but it is here shown as providedon its underside with a longitudinally extending reinforcing rib 14 and a transverse rib 15 simply for the sake of stiffness while permitting'the weight to be reduced, Furthermore the member' 10 is represented as provided at each 'side at points spaced from its center with apertured ears 15. This member 10 constitutes the main support for the conductor and must therefore be connected with some suitable suspension means. For this reason it is represented as provided with oppositely extending trunnions 1'7 projecting laterally from its center and preferably terminating in downwardly overhanging heads 18, these trunnions being located preferably at substantially the longitudinal center line of the conductor and being pivotally engaged within openings 19 in suspension links 20, these openings being represented as vertically elongated to permit initial passage'of the trunnion heads therethrough, these heads overlying the an 1 links at the bottom edges of the openings when the parts are in final position. It will therefore be seen that these overhanging heads 18 operate to prevent accidental removal or disengage'ment of the suspension links from the trunnions' The clamp further'includes an upper clamping member 21 of elongated form having a transverselycurved and longitudinally flaring seat 22 for engagement with the upper portion of the conductor. This member 21 is preferably seated within the groove or channel 11 in the lower clamping member as clearly indicated in Figure 3 and is also preferably provided at opposite sides and spaced from its transverse center with pairs of laterally expanding lugs 23 located inwardly of' bolt means such as the U-bolts 24 which extend over this upper clamping member with their legs extending through the apertured ears 16 and equipped with' nuts 25 between which and the lower faces of the ears there are preferablyloeated springlock washers 26 which will operate normally to prevent unscrewing of the "nuts and to apply a reactive force between the nuts and the ears which may be taken advantage of in a manner to be described. .The'purpose of the lugs 23 is to prevent longitudinal shifting of the member 21 and total detachment thereof from the remainder of the clamp when the bolt means is rendered ineifective in the manner to be described.

In addition to the above described, parts, the clamp comprises trigger means cooperating with the suspension means and the bolt means for rendering the latter ineffective when the clamp and the insulators supporting the same swing into an inclined position exceeding a certain angularity with respect to the vertical. This so called trigger means is represented as comprising a keeper 2'? located upon the upper clamping member 21 and'provided at the underside of its ends with curved downward projections 28 which provide line contacts with the upper clamping members 21 beneath the centers of the bight portions of the U-bolts, the purpose of these line contacts being to reduce the frictional resistance to longitudinal movement of the keeper under circumstances to be explained. Furthermore, in

tomarily circular in cross section throughout, and

as the top surfaces of the projections 29 are flat there will be only line contacts therebetween, this being likewise for the purpose of reducing frictional resistance to sliding movement of the keeper with respect to the U-bolts. In order that the position of the keeper 27 will be governedbythat of the suspension means, the keeper is shown as provided at its opposite edges with spaced laterally extending lugs 30 which are normally spaced somewhat from the edges of the links 20, or any other suspension means provided, for the purpose of permitting a certain amount of angular swinging of the clamp and the insulator string from which it is suspended, which string .is not shown, without therebeing'any effect upon the parts of the clamp, but which are adapted to be engaged by the edges of. the links and to be moved thereby in case said swinging movement exceeds a certain predetermined limit.

In assembling and installing the clamp, itwill be seen that the, lower member 10 is engaged against the conductor, after which the upper member 21 is placed in position upon the'latter, with the keeper 27 superposed upon the member 21, subsequently to which the U-bolts 24 are placed in position with their legs passing through the apertured ears 16. The spring washers 26, which though non-essential are preferably used, and the nuts are then applied to the U-bolts, the latter being turned down so that the U-bolts vwill cooperate with the members 10, 21 and 2'7 for applying a gripping action upon the conductor, the degree of pressure being governed by the extent to which the nuts are screwed down.

- Actually the nuts may be said to be screwed up though the word down is used in its popular:

sense, meaning that the nuts are tightened. The suspension links 20 may be connected with the trunnions -17 eitherbefore orafter the parts of the clamp have been assembled as described and it is of course apparent that these linksare in-- tended to be suspended from a string or chain of insulators. When the clamp is thus assembled it is apparent that the shiftable keeper member 27 is clamped tightly between the bights'of the U-boltsand the upper clamping member- 21,

the latter, together with the member '10, being of course pressed closely into clamping-relation to the conductor. However, as there are only line contacts between the bightsof the U-bolts and the members 29and only line contacts between the extensions or projections 28 and the clamping member 21 it will be understood that the keeper may he slid longitudinally without the expenditure of a tremendous amount of force. Of course the parts may be so shaped that there may be areas instead of lines of contact if such is found preferable.

In the operation, it will be clear that under ordinary circumstances the conductor is held firmly between the members 10 and 21 so that it cannot move longitudinally with respect thereto. Furthermore owing to the spacing of the lugs 30 from the edges of the suspension links there may be a certain limited swinging movement of the clamp and insulators supporting it without shifting the position of the keeper. This is desirable as permitting limited sagging of the conductor at either side of the clamp which might result from various causes and also as perm'itting movements which result from winds. However, in the event of an excessive strain at one side or the other of the clamp, such as might result from breakage of the conductor or an accumulation of ice or sleet thereon, it will be seen that the resultant movement of the clamp and its supporting insulators into an angular position with respect to the vertical greater than a certain predetermined amount, the links will engage against one pair of the lugs and apply pressure thereto which will result in moving the keeper 27 longitudinally. When this movement is of such extent that the projections-'29 ride at least partly out from under the bight port-ions of the U-bolts it is obvious that the bolts will become ineffective and will cease to hold the members 10 and 21 in tightly clamped-relation to the conductor so that the conductor may s'lip through the clamp until the strain at opposite sides of the latter is equalized. 'I'helu'gs 23 will prevent the upper clamping member 21 "from ever slipping out of proper relation to the remainder of the clamp and of course the'keep'er cannot slip out owing to the existence of the lugs 30 thereon.

Ordinarily, particularly if the conductor be wrapped with an armor or have some exteriorly applied means thereon for protective or other purposes, it is not desirable to have the clamp regrip the conductor as it might occur that the regripping would take place at an unarmored portion of the conductor, the armored portion having slipped through and beyond the clamp. However, if it should be desired to have the clamp regrip the conductor, for example in accordance with the same principle disclosed in my co-pending applications for patents for Releasing clamps, filed September 20, 1928 and given Serial Nos. 307,137 and 307,138, the keeper 27 may simply have wedge shaped ends as shown at 31 in Figure 7 so that after the clamp has released and the conductor has slipped through and the clamp and its supporting insulator string returned to normal or vertical position the keeper will be slid back into its normal or intermediate position with the higher portions of the wedges reengaging beneath the bights of the U-bolts. This form will not release as abruptly as the first described form as will of course be apparent but it will nevertheless operate to permit slipping of the conductor.

the upper clamping member 21.

' In Figure 1 the nuts are shown as screwed down to such an extent that the spring washers 26' are entirely compressed. Thisneed not be the case as it may be desirable to provide a slightly yieldable spring reactance. Such being the case I have shown, in'-Figure '8, the spring washers as slightly sprung so as to be yieldable. This arrangement makes-it still easier for therke'eper member 27 to slide into its released position; regardless of whether the keeper member have its ends formed with the projections '29 as shown in Figure 1 or whether it'h'ave'wedge shaped ends as shown in Figures '7 and 8'. l

In some localities, for instance where there is no danger of sleet or iceaccumulating' onthe conductor, and in other circumstances, 'it may not be desirable to have a releasing clamp as one of the fixed variety is suflicie'nt for all purposes. If the releasing action is not desired, it is a simple matter to omit the keeper-27 and to screw down or tighten the nuts-25 suiiiciently that-'the bi'ght portions of the u boltsw-ill engagedirectly upon If necessary shorter U-bolts can be used. In this way it is apparent that my clamp is convertible for use m0 either as arelea'sing or a non-releasing clamp as the requirements of service may dictate, the latter arrangement being clearly illustrated in Figure 9.

' From the foregoing description and a study of .the drawings it will be apparent that Ihave thus provided a very simply constructed and inexpensiveclamp which maybe said to be trigger 0perated and which does not depend in any wayor at any time .upon the use of springs for either the holding or the releasing a'ction. In view of the fact that the clamp embodies bol't means for maintaining. the clamping relation upon the conductor it is obvious that the grip will be positive and may, moreovenbe initially varied, or varied "ii at any time if found desirable, for instan'ce'd'epending upon the diameter of the-conductor, its

material andtherefore its capability of withz standing pressure without mutilation, the length of spans, :and the like. construction, operation and advantages should be --ieadily apparent to one s'k'illed in the-art without vfurther explanation. i

. .While I have shown and described the pieferred'embodiments of theinvention', it should be understood that the disclosure is merely an exemplifi'cati'on of the principles involved as the right is reserved to make all such changesin the details of construction as Willwiden the field or utilityand increase the adaptability of the device 330 provided such changes constitute nodeparture from the spirit of-the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

Itis thought that the 1. A suspension clamp comprising a pair of ii- 35 clamping members engageable upon opposite sides of a conductor, bolt means urging said clamping members toward each other, suspension means, and trip operated means reacting directly against the bolt means for rendering said 'ili'O bolt means ineffective upon swinging of said suspension means beyond a predetermined limit.

2. A releasing clamp comprising a lower clamping member adapted to support a conductor, an

upper clamping member, suspension means piv-i id,

otally connected with the lower clamping mem ber, bolt means urging said clamping membe toward each other, and means directly contacting the bolt means and operating upon'lateral swinging of the suspension means beyond a 1 clamping members in gripping relation to the determined extent to render said bolt means ineffective.

3. A releasing clamp comprising a lower clamping member adapted to support a conductor, an

upper clamping member, suspension means piv- 'otally connected with the lower clamping member, bolt means urging said clamping members towardeach other, and means reacting directly against the bolt means and one clamping memher and operating upon lateral swinging of the suspension means beyond a predetermined extent to render said bolt means ineffective, said last named means being trip operated.

4. A clamping device comprising a clamping member adapted to support a conductor, a second clamping member, bolt means engaging both clamping members, suspension means connected with one clamping member, means coacting with the upper clamping member, and engaging the bolt means for maintaining the clamping relation, and means operable upon swinging movement of the suspension means through a predetermined are for rendering said last named means ineffective.

5. A suspension clamp comprising a pair of clamping members engageable upona conductor, rigid and immovable retaining means engaging the clamping members, suspension means pivotally connected with one clamping member, and trip operated means for slidably releasing said ,retaining'means upon swinging movement ofthe conductor beyond a predetermined limit.

' 6. A suspension clamp comprising a plurality of clamping members engageable upon a conductor, suspension means connected with the clamp, bolt means normally maintaining said clamping members in gripping relation to the conductor, and means movable longitudinally of the clamping members upon swinging movement of the suspension means beyond apredetermined extent for rendering said bolt means ineffective.

' '7. A suspension clamp comprising a plurality .of: clamping members engageable upon a conductor, suspension means pivotallyconnected "with the clamp, bolt'means normally maintaining the clamping members in gripping'relation to the conductor, and'means normally engaging the bolt means and directly engageable by the suspension means upon swinging movement thereof beyond a predetermined limit for rendering the bolt meansineffective.

8. A suspension clamp comprising. a plurality of clampingmembers engageable upon a conducitor, suspension meanspivotally connected with the clamp, bolt means normally maintaining the conducton'and means normally engaging the bolt means and directly engageable by the suspension means upon swinging movement thereof beyond a predetermined limit for rendering the bolt means ineffective, said last named means being slidable longitudinally of the clamping members.

9. A suspension clamp comprising a plurality of clamping members engageable upon a conductor, suspension means pivotally connected with the clamp, bolt means normally maintaining the clamping members in gripping relation to the conductor, and means normally engaging the bolt means and directly engageable by the suspension means upon swinging movement thereof 'beyond a predetermined limit for rendering the bolt means ineffective, said last named means comprising a keeper interposed between one clamping member and the bolt means and slidable' along the former.

10. A suspension clamp comprising upper and lower clamping members engageable upon a conengaged upon, the upper clamping member, U-

bolts connecting the clamping members and having their bight portions engaging over said keeper member, and means coacting with the suspension means upon swinging movement thereof beyond a predetermined extent, for moving said keeper member with respect to the U -bolts and rendering the latter ineffective, said means comprising projections on the keeper member engageable by the suspension means.

.12. A suspension clamp comprising upper and lower clamping members engageable upon a conductor, suspension means pivotally supporting the assembled clampingmembers, a keeper member engagedupon the upper clamping member, U-

bolts connecting the clamping members and having their bight portions engaging over'said keeper 7 member, and means coacting with'the suspension means upon swinging movement thereof beyond a predetermined extent, for moving said keeper member with respect to the U-bolts and rendering the latter ineffective, said keeper member being removable and said U-bolts being adapted to have their bight portions engage the upper clamping member directly to convert theclamp into one o the non-releasing type. I e

. JOHN MILTON JE'STER. 

